How to find Patents?

On the Web

Esp@cenet
http://www.espacenet.com
Gives access to patent information from around the world. Coverage depends on country. Full text information for many patents is available.

USPTO (US Patent and Trademark Office)
http://www.uspto.gov/patft/
Coverage is from 1790 onwards for issued US Patents, full-text from 1976 onwards. Published applications are available from March 2001.